LOW H2 CO RATIO SYNTHESIS GAS CONVERSION TO METHANOL IN A TRICKLE-BEDREACTOR/

The performance of a trickle bed reactor for methanol synthesis over a Cu/ZnO/Al2O3 Catalyst was investigated. The pressure was kept constan t at 5.2 MPa; and the CO/CO2 ratio was maintained at 9.0 throughout th e investigation. The effects of time on stream, space velocity, H-2/(C O + CO2) ratio, and liquid-phase flow rate on methanol productivity we re studied at 508, 523, and 533 K. The H-2/(CO + CO2) ratios were set at 0.5, 1.0, and 2. The space velocity was in the range 3000-20000 L/( h kg of catalyst) at 523 K and 3000-8000 L/(h kg of catalyst) at 508 a nd 533 K. The feed gas along with an inert oil was passed over a fixed bed of catalyst particles of size 500-600 mum. The product was mainly methanol with small amounts of water. The catalyst deactivated during the first 100 h on stream and reached a steady-state activity which w as maintained for over 1000 h on stream. Methanol and water productivi ties increased with space velocity and with H-2/(CO + CO2) ratio, as w ell as with temperature. Productivities as high as 39.5 mol of methano l/(h kg of catalyst) were achieved. The results are compared to slurry reactor data at the same and similar conditions.